Trailers attached to pull vehicles are commonly used to transport machinery, livestock, and other goods. When the trailer is unhitched from the pull vehicle, the trailer and its goods are subject to theft by undesired coupling to some other towing or pull vehicle. Trailer hitches are of a limited variety, frequently being of standard types of shapes. Examples are ball and socket hitching devices in which the trailer coupler consists of a socket which mounts on a ball attached to the pull vehicle; king pin hitches which consist of cylindrical posts containing circumferential recesses and fit into matching openings mounted on the pull vehicle; and gooseneck hitches. The typical or standard gooseneck hitch consists of an irregular or non-symmetrical coupler foot plate attached to the lower end of a generally vertical post, the upper end of which post is attached to the trailer. The post in gooseneck hitches may have a horizontal component or beam at its upper end, which horizontal component or beam attaches to the front of the trailer. The coupler at the lower end of the post generally connects with a receiving device on the pull vehicle. The coupler itself consists of front and rear facing portions of different shapes and configurations.
To prevent undesired coupling of trailers to other pull vehicles, locks have been devised to fit over the ball or over or within the socket of a ball and socket-type hitch. Similarly, locking devices have been devised to enclose the king pin or hitch post of trailers having king pin-type couplers. Such locking devices, however, are not generally used or adapted for use with gooseneck hitch couplers.
There is a need for a durable, inexpensive, simply operated, and effective trailer hitch lock for trailers with gooseneck hitches having non-symmetrical or irregularly shaped couplers. Locking devices for king pin or ball and socket hitches cannot be used on gooseneck couplers, because such locking devices will not fit around or be attachable to the coupler of a gooseneck hitch. The gooseneck trailer hitch lock should surround the coupler of the gooseneck, thus cooperating with it to obstruct the coupler as to prevent undesired coupling with another towing vehicle. Such locking device should further contain means to prevent its undesired removal from the coupler.